Jeff saw two creatures (very similar to him, but his mind was too limited to figure out what they were) in front of him.
the Chronivac had turned the factory into a cave and it looked like a savannah outside. In addition, the changes also occurred for Jeff, Kevin and Rose: Their mind was regressed to that of homo erectus, while physically their clothes changed. Kevin and Jeff were slightly more muscular, and their private parts were covered with a narrow thong. Rose instead had some more aesthetic changes: like the cave women of the movies, her private parts were covered by a fur-bikini, which left little to the imagination. Over his head he had a bone that tied his hair.
Cavewoman Rose, after realizing that there were two males of her species with her, began primitive socialization, taking off his clothes and turned around presented her ass to the expecting cavemen.